不同热处理对Al-5.6Mg合金板材表面组织和阳极氧化膜组织的影响

Effect of Different Heat Treatments on Surface Microstruc-tures and Anodic Oxide Film Structures of Al-5.6Mg Alloy Sheets

摘要:

研究了不同中间退火热处理对Al-5.6Mg合金轧制薄板表面组织和阳极氧化膜组织的影响。结果表明：在中间退火过程中，用连续退火代替箱式退火，试样表面晶粒尺寸可减小约60%，Mg析出相（Mg₂Al₃）尺寸可减小约67%；在晶粒尺寸、析出相和织构的共同影响下，经连续中间退火和低温稳定化退火后阳极氧化，获得了最高的光泽度。均匀的微观结构有利于减少氧化膜的不均匀溶解，获得厚度均匀、光泽度高的阳极氧化膜。

Abstract:

The effect of different intermediate annealing heat treatments on the surface microstructures and anodic oxide film structures of rolled Al-5.6Mg sheets was studied. The results show that when the continuous annealing is used to control microstructures of the sheets instead of the static state annealing in the intermediate annealing process, the surface grain size of the sheets can be reduced by about 65.7%, and the size of the Mg precipitation phase (Mg₂Al₃) can be reduced by about 67%. Under the combined influence of grain size, precipitation phase, and texture, the highest glossiness can be obtained, which is attributed to continuous intermediate annealing and stabilization annealing at low temperature. The uniform grain and precipitation structures is beneficial to reducing the inhomogeneous dissolution of the oxide film and to obtain the anodic oxide film with uniform thickness and high glossiness.